Stick (Smaw) Basic Welding Technique; Effects Of Stick Welding Various Materials - Firepower MST 180i Operating Manual

Firepower MST 180i

4.03 Stick (SMAW) Basic Welding Technique

Size of Electrode
The electrode size is determined by the thickness of metals being joined and can also be governed by the type of welding
machine available. Small welding machines will only provide sufficient current (amperage) to run the smaller size electrodes.
For thin sections, it is necessary to use smaller electrodes otherwise the arc may burn holes through the job. A little practice
will soon establish the most suitable electrode for a given application.
Storage of Electrodes
Always store electrodes in a dry place and in their original containers.
Electrode Polarity
Electrodes are generally connected to the ELECTRODE HOLDER with the Electrode Holder connected positive polarity. The
WORK LEAD is connected negative polarity and is connected to the work piece. If in doubt consult the electrode data sheet
or your nearest Accredited Firepower Distributor.

4.04 Effects of Stick Welding Various Materials

High Tensile and Alloy Steels
The two most prominent effects of welding these steels are the formation of a hardened zone in the weld area, and, if suitable
precautions are not taken, the occurrence in this zone of under-bead cracks. Hardened zone and under-bead cracks in the
weld area may be reduced by using the correct electrodes, preheating, using higher current settings, using larger electrodes
sizes, short runs for larger electrode deposits or tempering in a furnace.
Manganese Steels
The effect on manganese steel of slow cooling from high temperatures is to embrittle it. For this reason it is absolutely
essential to keep manganese steel cool during welding by quenching after each weld or skip welding to distribute the heat.
Cast Iron
Most types of cast iron, except white iron, are weldable. White iron, because of its extreme brittleness, generally cracks
when attempts are made to weld it. Trouble may also be experienced when welding white-heart
malleable, due to the porosity caused by gas held in this type of iron.
Copper and Alloys
The most important factor is the high rate of heat conductivity of copper, making pre-heating of heavy sections necessary
to give proper fusion of weld and base metal.
Types of Electrodes
Arc Welding electrodes are classified into a number of groups depending on their applications. There are a great number
of electrodes used for specialized industrial purposes which are not of particular interest for everyday general work. These
include some low hydrogen types for high tensile steel, cellulose types for welding large diameter pipes, etc The range of
electrodes dealt with in this publication will cover the vast majority of applications likely to be encountered; are all easy to use.
Arc Welding Practice
The techniques used for arc welding are almost identical regardless of what types of metals are being joined. Naturally
enough, different types of electrodes would be used for different metals as described in the preceding section.
Welding Position
The electrodes dealt with in this publication can be used in most positions, i.e. they are suitable for welding in flat, horizontal,
vertical and overhead positions. Numerous applications call for welds to be made in positions intermediate between these.
Some of the common types of welds are shown in Figures 4-15 through 4-22.
BASIC WELDING GUIDE 4-8 Manual 0-5339